1. Field of the Invention
The present invention relates to an electronic device, a control method of the electronic device, a program, and a storage medium. More particularly, the invention relates to an electronic device for controlling a touch detection threshold value of a touch sensor of an electric capacity type, a control method of the electronic device, a program, and a storage medium.
2. Description of the Related Art
In recent years, the number of electronic devices having touch sensors such as smartphone, digital camera, and the like is increasing. As a type of touch sensor, there are various types such as pressure sensitive type, electric capacity type, optical type, and the like. In any of those types, by setting a threshold value with respect to a change of a sensor output, the presence or absence of a touch input is discriminated. A touch detection sensitivity depends on such a threshold value.
The Official Gazette of Japanese Patent Application Laid-Open No. H05-143226 discloses a coordinate input apparatus in which a sensor area is divided into a plurality of small areas and an individual threshold value is set for every small area, thereby adjusting the touch detection sensitivity in accordance with the area.
The Official Gazette of Japanese Patent Application Laid-Open No. 2010-257046 discloses a method (sensitivity calibration) whereby an electric capacity value in a state where the finger of the user and a dielectric body do not touch an electrode is set to a reference capacity (base line value), and when an input by the finger or the like is detected, approaching and touching states of the finger are detected by using a difference value between the electric capacity value which is output from the electrode and the base line value.
The touch sensor of the electric capacity type discriminates the presence or absence of the touch input by setting the threshold value with respect to the change of the capacity value as a sensor output. The capacity value changes in accordance with an area of a touching portion of a touch input. However, in an end portion of the sensor area, there is a case where the finger of the user or the like happens to touch the sensor area in such a manner that the touch by the finger spreads over the inside and the outside of the sensor area. In such a case, it fails to ensure an enough area of a touch with the inside of the sensor area. There is, consequently, such a problem that if a touching is provided in a manner similar to that in an area in which a provided touch does not include the outside of the sensor area, the capacity value decreases and the touch detection sensitivity deteriorates.